The invention relates to blind rivet installation apparatus and automated methods for operating such apparatus. More particularly, the invention relates to automated and semi-automated rivet installation systems with built-in diagnostic systems for increased reliability.
A blind rivet comprises a tubular rivet body in which is mounted a mandrel having a head portion at the narrow end of the stem so that when this mandrel is pulled back in the rivet it upsets the rivet. When pulling-back of the mandrel is resisted with a predetermined force, the mandrel breaks off. A riveter that operates with such rivets typically has a housing formed at its front end with an aperture through which the rivet mandrel is engaged. Within the housing is a chuck that engages tightly around the mandrel and actuating mechanism which holds this chuck backwardly, thereby upsetting the rivet and breaking off the mandrel. The broken-off mandrel is removed from the riveter, perhaps by a collection system which avoids hazards due to broken-off mandrels ejecting from the riveter and collecting on the floor.
These tools fall generally into the classification of hand operated or power operated tools. An example of a hand operated tool is illustrated in U.S. Pat. No. 3,324,700. The power operated tools are for heavy duty continuous assembly line type operation, and examples of such tools are illustrated in U.S. Pat. Nos. 3,088,618 and 3,254,522. It is known to automate the process of feeding rivets to the riveter tool, as for example shown in U.S. Pat. No. 3,367,166 and U.S. Pat. No. 4,027,520. It is also known to automate the mandrel collection process as taught, for example, in U.S. Pat. No. 4,062,217, and U.S. Pat. No. 4,275,582. The most common approach to automatic rivet feed and disposal uses hydraulically or pneumatically powered mechanisms for guiding blind rivets to the riveting tool and extracting broken off mandrels therefrom.
One common shortcoming of prior art apparatus for automated or semi-automated feeding of rivets to the riveting tool is the failure of such systems to take into account the possible improper feeding of rivets to the riveter tool, which especially in the case of faulty rivets can fail due to misalignment between the rivet and the rivet engaging mechanism. Such misalignment can lead to jamming, and repeated unsuccessful attempts to insert a rivet can cause damage to the apparatus.
Other stages of the process of feeding rivets from a supply to the riveting tool and collecting broken off mandrels therefrom also raise risks of malfunctions. For the above reasons, the prior art has failed to successfully solve the problem of completely automating the rivet installation process in a reliable manner.
Accordingly, a primary object of the invention is to provide automated and semi-automated rivet installation systems of improved reliability. A related object is to provide the capability in such systems to diagnose and report to the operator various fault conditions.
Another object of the invention is to track and report the performance of the automated rivet installation apparatus.